Design And Analyses Of Certificateless Proxy Ring Signcryption Scheme

As special digital signature technology, ring signature and proxy ring signature were widely used in the anonymous electronic voting、anonymous elections and many anonymous applications because of their special features.It has great theoretical value and practical significance for studying on them deeply. In this paper, many ring signcryption and proxy ring signature schemes were researched deeply, and we made some improvements on them.Firstly, a self-certified ring signcryption scheme based on DLP was proposed, which was improved based on the scheme proposed by Yu. There were two shortages on the scheme proposed by Yu:one is that scheme was designed based on bilinear pairings. So the scheme is time-consuming, and computation efficiency is low. The other one is scheme did not have the function that the real signer can verify his identity publicly by herself. For above two problems, other operations instead bilinear pairings were used in the design of new scheme, so the computation efficiency was improved greatly. As well as the new scheme realized the function that the real signer can verify his identity publicly by herself. So new scheme has better practicability. And we proved its security under the CDH (Computational Diffie-Hellman) assumption and the hardness of DLP.Existing proxy ring signature schemes only have authentication function, and did not have encryption function. In order to realize these two functions at the same time, a certificateless proxy ring signcryption scheme was proposed in this paper, which is combined proxy ring signature with signcryption technology for first time. Because we can achieve signature and encryption function within a logical step by using signcryption technology, so simplified the steps of signature and encryption on data, and the computational efficiency was improved. Moreover, the design of new scheme is based on DLP and certificateless public key cryptography, so it did not exits communication overhead key management problem and dishonest KGC attacks. In the last, we also proved its security under the CDH (Computational Diffie-Hellman) assumption and the hardness of DLP.